The present invention relates generally to personal identification or verification systems and, more particularly, to systems that automatically verify a person's identity before granting access to something of value. Traditionally, keys and locks, or combination locks, have been used to limit access to property, on the theory that only persons with a right to access the property will have the required key or combination. This traditional approach is, of course, still widely used to limit access to a variety of enclosed spaces, including rooms, buildings, automobiles and safe deposit boxes in banks. In recent years, mechanical locks have been supplanted by electronic ones actuated by encoded plastic cards, as used, for example, for access to hotel room doors, or to bank automatic teller machines (ATMs). In the latter case, the user of the plastic card as a "key" to a bank account must also supply a personal identification number (PIN) before access is granted.
Many automobiles are protected both by locks and by intrusion alarms, which are typically activated and deactivated using a small radio or infrared transmitter carried by the car owner as a key-chain fob. Although this type of device is convenient, its loss by the owner may render the vehicle just as vulnerable to theft as if mechanical keys had been used for protection.
Today, a person still needs to carry a variety of keys for access to home, workplace and car, and an ever expanding stack of plastic cards for access to financial assets, such as bank accounts and store charge accounts. Today's busy person must memorize several passwords and PINs for use in conjunction with the plastic cards, and for use to access computer software that may or may not require an access card as well. Moreover, all of the foregoing devices for limiting access are subject to theft, duplication and misuse. Assets protected by mechanical keys are the most vulnerable, of course, but assets protected by combinations, passwords and PINs are also subject to illegal entry by unauthorized users who have stolen, deduced or guessed the appropriate combination, password or PIN.
Accordingly, there is a widely felt need for a more reliable technique for limiting access to personal property and other valuable assets. Ideally, the technique should positively verify the identity of the person seeking access, and should eliminate the need to carry multiple keys and scannable cards, and the need to memorize combinations, passwords and PINs. The present invention satisfies this need.